NEW YORK (AP) — Health officials say an Illinois man has apparently picked up an infection from the only American diagnosed with a mysterious Middle East virus, but the man has not needed medical treatment.

The first U.S. case of Middle East respiratory syndrome was confirmed earlier this month in Indiana, where a man fell ill shortly after arriving from Saudi Arabia where he lived.

The Centers for Disease Control and Prevention said Saturday that tests completed Friday show the Illinois man probably was infected with the virus after having close contact twice with the MERS patient in Indiana.

Most cases of MERS have been in Saudi Arabia or elsewhere in the Middle East.

A second U.S. case was confirmed last week in a man from Saudi Arabia who was visiting Florida.

The CDC says that it is attempting to track down individuals who may have come into contact with either MERS patients. The CDC has also placed advisory notices in airports and is said to be closely surveying the MERS virus in the U.S.